Unsaturated alkyl esters of aryl phosphonic acids



Patented Aug. 19, 1947 UNSATURATED ALKYL ESTERS F ARYL PHOSPHONIC ACIDSArthur Dock Fon Toy, Chicago, Ill., assignor to Victor Chemical Works, acorporation of Illinois No Drawing. Application October 29, 1945, SerialNo. 625,459

4 Claims. (Cl. 260-461) This invention relates to a new class ofunsaturated phosphonate ester compounds having the general formulawherein Ar represents aryl and alkaryl hydrocarbon radicals and R and Rrepresent hydrogen and alkyl hydrocarbon radicals. The new estercompounds may be produced by reacting aryl phosphorus oxydichlorideswith beta, gamma unsaturated alkyl alcoholsunder suitable reactingconditions.

The aryl phosphorus oxydichloride starting materials may be suitablyprepared by the method of my U. S, patent application Serial No.517,438, filed January 7, 1944, which comprises reacting an arylphosphorus dichloride with phosphoric anhydride and chlorine, andseparating the and phosphorus oxydichloride from the reaction products.The reaction involved may be expressed by the following equation:

The beta, gamma unsaturated alkyl alcohols suitable for use in makingthe products of the present invention may be designated by the generalformula:

HO CHr-C=CHR The new beta, gamma unsaturated alkyl esters of arylphosphonic acids may be prepared by reacting the sodium alcoholates ofthe unsatu rated alcohols with aryl phosphorus oxydichloride but suchprocedure is difficult and the yields are poor. It has been found,however, that greatly improved yields and better products may beobtained by reacting the beta, gamma unsaturated alcohol with the arylphosphorus oxyf 2 dichloride in the presence of pyridine with or withoutan inert solvent such as benzene, hexane, etc.

The following examples illustrate my improved method of production.

Example 1 In a 2 liter 3-necked flask equipped with-a stirrer, athermometer, and a dropping funnel were placed 116 g. (2 moles) of allylalcohol, 158 g. (2 moles) pyridine, and 440 grams of technical hexane.To this solution was added with stirring 195 g. (1 mole) ofphenylphosphorus oxydichlo ride (CeHsPOCh). The phenylphosphorusoxydichloride was slowly added over a period of about 2 hours whilmaintaining the reaction mixture at a temperature of from 2 to 7 C. Themixture was stirred for another hour and the white precipitate ofpyridine hydrochloride formed in the reaction was filtered oil andwashed with 250 cc. of hexane. The filtrate consisting of an oily layerand a hexane layer was separated and the two layers processedseparately. The hexane layer was distilled at a temperature of 31 to 35C. under 150 mm. pressure to remove the hexane solvent. The residualliquid was gradually heated at 10 mm. until the liquid temperaturereached C. It was then heated to 120 C. at less than 5 mm. pressure, andfinally distilled at less than 2 to 3 mm, pressure. A little copperpowder was added prior to the distillation to act as an inhibitoragainst polymerization. The oily layer from the original filtration wasdiluted with cc. of benzene and washed with 4 successive 25 cc. portionsof water. The washed oil-benzene solution was then dried, the benzenedistilled oil, and the ester compound distilled and combined with theportion of the prodnot obtained from the hexane layer. A total of 178 g.of the ester product representing a 75% yield was recovered.

Example 2 In an alternate procedure without the use of the hexanesolvent medium, the diallyl phenyL phosphonate ester was prepared asfollows:

In a flask equipped as in Example 1 were placed 232 g. (4 moles) ofallyl alcohol and 316 g. (4 moles) of pyridine. To this solution wasslowly added with stirring 390 g. (2 moles) of phenylphosphorusoxydichloride over a period 01' about 4 hours. The temperature of thereaction mixture was maintained at about 2 to 5 C. by means of anice-salt bath. The mixture was then stirred for another hour whileallowing the tem- I perature to rise gradually to room temperature.

' tions employed in. Example 1.

An 83% yield of the diallyl phenylphosphonate ester was obtained in thisexample.

Example 3 The procedure of Example 2 was repeated using double thequantities of reactants and employing the following modification. Afterthe reaction was completed and the oily layer separated, it wasdistilled under reduced pressure without first washing with alkalisolution or water. In the distillation the heating was carried outslowly so as to maintain the pressure at less than 20 mm. up to 50 C.(liquid temperature), less than mm. up to 100 0., less than 5 mm. up to120 C., and less than l-2 mm. up to the distillation temperature. Theyield of the distilled product was 777 grams or 81.6% of theoretical.

The purified diallyl phenylphosphonate obtained in the above exampleshad the following physical properties:

germ Colorless liquid oiling point l26128 C. at 1 mm.

Specific gravity... 1.112 at 25 C.

Refractive index l.5l06 at 28 C.

Acidity 0.l cc. N/l0 NaOIl/lO cc. (phenolphthalein indicator) Surfacetension 39.3 dynes/cm. at 28 C.

Viscosity 8.5 tces ti oises at 25 0., 3.6 centipoises a Freezing pointVery viscous at 7()C.

Solubility in water 2.0 g./liter Flash point (open cup)- 335 F. Firepoint (open cup)--- 34 F. Analysis 13.5% P (found). 13.0% (theory) Thereaction involved in the above examples may be designated by thefollowing equation:

crnirocll 2HOCHr-CH=CH: 20.11.:

OCHzCH=CHi Pyridine may be recovered from the pyridine hydrochlorideresidue by known means for reuse in the process.

7 Example 4 Dimethallyl phenylphosphonate was prepared in accordancewith the procedure described in Example 2 except that 288 g. (4 moles)of meth- 4 Example 5 Dimethallyl tolylphosphonate OCH: =CH| CHSCGHGPOCHIC==CHI was prepared in accordance with the following procedure.

70 g. (0.335 mole) of tolylphosphorus oxydichloride (CHaCuHlPCh wasadded with stirring to a mixture of 48.5 g. (0.67 mole) of methallylalcohol and 53 g. (0.67 mole) of pyridine. The temperature wasmaintained at 2 to 5 C. during the addition period by means of anice-salt bath. The reaction mixture was allowed to rise to roomtemperature and 50 cc. of water added to dissolve out the pyridinehydrochloride. The oily ester layer was separated by means of aseparatory funnel and dried by stirring with anhydrous magnesiumsulfate. The magnesium sulfate was filtered off and the ester productpurified by distillation under vacuum in the presence of a small amountof a polymerization inhibitor. The redistilled dimethallyltolylphosphonate ester product had a boiling point of l37139 C. at 3-4mm. pressure and a refractive index of 1.5065 at 27 C. The yield of pureproduct in this example was 63 grams which represents a yield of 67.2%of theoretical.

Example 6 Following the procedure of Example 5, tolylphosphorusoxydichloride and allyl alcohol were reacted in the presence of pyridineto produce the diallyl tolylphosphonate ester. The redistilled ester wasa water-white liquid having a boiling point of 127128 C. at 3 mm.pressure and a refractive index of 1.5097 at 28 C. It had a phosphoruscontent of 12.4% compared to the theoretical value of 12.3% for theformula 0 ll CHQCBH. P(0 CHiOH-CHl)! The beta, gamma unsaturated alkylesters of aryl phosphonic acids of this invention tend to polymerize attemperatures near their boiling points so care must be taken inpurifying them by distillation methods. This tendency to polymerize issatisfactorily inhibited by the addition of small amounts of copper,bronze, copper compounds, etc., during the distillation.

The proportions employed in the above examples are not critical withrespect to the use of excess amounts of the alcohol and pyridine.Excesses of either the alcohol or pyridine may be separated andrecovered after the ester forming reaction is completed.

The pyridine hydrochloride separated in the above examples may bereconverted by known means to pyridine for reuse in the process.

The ester forming reactions in the above examples were carried out attemperatures sufficiently low to avoid decomposition of the unsaturatedalcohols by HCl liberated in the reaction prior to its absorption by thepyridine. Generally a temperature of the order of 10 C. will besatisfactory, though a temperature of less than 5 C. is preferred.

The foregoing detailed description has been given for cleamess ofunderstanding only, and no unnecessary limitations should be understoodARTHUR DOCK FON TOY. REFERENCES CITED 6 UNITED STATES PATENTS Name DateConary Dec. 31, 1940 Ginson Dec. 23, 1930 Woodstock Nov. 22, 1938Kosalopofi Nov. 20, 1945 Kropa, July 22, 1941 FOREIGN PATENTS CountryDate Germany Feb. 13, 1931 OTHER REFERENCES Bellstein, "Handbuch derOrganische Chemie,"

The following references are of record in the 4t V D- 4 3 flle of thispatent:

